Long story short, the badge assignment script I have searches for users first by user_nicename, then if no match, by user_login. Since trac only shows user_login, I should probably switch that search ordering. (Though in general it'd be easier if users were only ever referred to by nicename, here and elsewhere on wp.org. Anyhow.)

@pareshradadiya-1: I have assigned the Core Contributor badge to your account.